According to comScore Media Metrix, weather sites showed a huge spike in traffic thanks to the hurricane. Compared to the average for the previous four Thursdays, Weather.com traffic was up 92 percent to 3.5 million visitors yesterday. Likewise, smaller sites felt the surge. AccuWeather was up 90 percent to 380,000 visitors and government sources like the National Oceanic and Atmospheric Administration’s Web site was up 210 percent to 940,000 visitors.

More traffic is usually good news for publishers and advertisers, but it also brings more pressure to deal with the flood of traffic.

According to Joe Fiveash, Weather.com’s senior vice president for business and product development, the site was able to mostly withstand the onslaught by switching at times to a static page with the status of the hurricane, instead of its regular dynamic site. At about midday, when traffic surged, Weather.com turned to the ad-free static page to take pressure off its 86 overtaxed application servers.

“We make sure that frequently updates information is available at all times on a static page,” he said. “What you see in the rare event when we have to go to this mode, you’ll see a very frequently updated static page with the latest information on the hurricane.”

Fiveash said the company saw three to four times its usual activity on the site. He estimated that just 2 percent of visitors were shunted off to the ad-free page, with advertiser Scott’s reaping the benefit of the extra traffic Isabel brought. The lawn-product manufacturer bought that day’s placement on Weather.com’s homepage. (Weather.com does not sell its homepage on a CPM basis.)

Roopak Patel, public services division analyst at Web performance company Keynote Systems, said sites are wise to take steps like offering static pages over dynamic content during times of traffic surges, even if it meant stripping out some advertising.

“You’re depending on multiple variables to build the [dynamic] page,” he said. “When it takes five to ten requests to build a page, you’re asking for trouble.”